U.S. patent number 11,006,540 [Application Number 15/772,237] was granted by the patent office on 2021-05-11 for circuit board for mechanically fastening a housing.
This patent grant is currently assigned to TRIDONIC GMBH & CO KG. The grantee listed for this patent is TRIDONIC GMBH & CO KG. Invention is credited to Wolfgang Weber.
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United States Patent |
11,006,540 |
Weber |
May 11, 2021 |
Circuit board for mechanically fastening a housing
Abstract
The invention relates to a circuit board (1), preferably for a
circuit for operating a lighting means, comprising a retaining bow
(2), which is arranged on a planar top side (11) of the circuit
board (1) and mechanically connected to the circuit board (1); and
comprising a through-bore (3), which is arranged at least partially
below the retaining bow (2); wherein the through-bore (3) has at
least one taper (31) and wherein a housing (5) for protecting the
circuit board (1) can be mechanically fastened by means of the
retaining bow (2) and the taper (31). The retaining bow (2) is
arranged on the circuit board (1) by means of a solder joint (32).
The invention further relates to a system for a circuit for
operating a lighting means and to a method for fastening a housing
(5) to a circuit board (1).
Inventors: |
Weber; Wolfgang (Fu ach,
AT) |
Applicant: |
Name |
City |
State |
Country |
Type |
TRIDONIC GMBH & CO KG |
Dornbirn |
N/A |
AT |
|
|
Assignee: |
TRIDONIC GMBH & CO KG
(Dornbirn, AT)
|
Family
ID: |
1000005542912 |
Appl.
No.: |
15/772,237 |
Filed: |
November 7, 2016 |
PCT
Filed: |
November 07, 2016 |
PCT No.: |
PCT/EP2016/076879 |
371(c)(1),(2),(4) Date: |
April 30, 2018 |
PCT
Pub. No.: |
WO2017/084906 |
PCT
Pub. Date: |
May 26, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200288596 A1 |
Sep 10, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Nov 19, 2015 [DE] |
|
|
10 2015 222 874.6 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K
9/0039 (20130101); H05K 1/0215 (20130101); H05K
7/1427 (20130101); H05K 7/142 (20130101); H05K
3/325 (20130101); H05K 2201/10113 (20130101); H05K
2201/09063 (20130101); H05K 2201/09072 (20130101) |
Current International
Class: |
H05K
5/00 (20060101); H05K 9/00 (20060101); H05K
3/32 (20060101); H05K 1/02 (20060101); H05K
7/14 (20060101) |
Field of
Search: |
;361/753,760,807,809,810
;174/138E,138G |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
9115131 |
|
Mar 1992 |
|
DE |
|
10 2009 053 206 |
|
May 2011 |
|
DE |
|
2729042 |
|
Jul 1996 |
|
FR |
|
2474509 |
|
Apr 2011 |
|
GB |
|
2007035933 |
|
Feb 2007 |
|
JP |
|
Other References
Austria Search Report dated May 19, 2016 in co-pending Austria
Application GM 397/2015. cited by applicant .
German Search Report dated Jul. 21, 2016 in priority German
Application 10 2015 222 874.6. cited by applicant .
PCT Search Report dated Feb. 13, 2017 in parent PCT Application
PCT/EP2016/076879. cited by applicant.
|
Primary Examiner: Bui; Hung S.
Attorney, Agent or Firm: Andrus Intellectual Property
Law
Claims
What is claimed is:
1. A lamp driver system comprising: a housing (5) having a
retaining element (4) extending from the housing, said retaining
element having at least two retaining flaps (41) and a slot (42)
disposed between the retaining flaps; a PCB board comprising a
planar upper surface and a planar lower surface with an elongated
through hole passing through the PCB board from the upper surface
to the lower surface, the elongated through hole including two
tapering elements each disposed on opposing longitudinal sides of
the through hole; components of a lamp driver circuit mounted on
the PCB board; and a retaining bracket (2) connected to the PCB
board and passing over or through the through hole in the PCB
board; wherein the longitudinal sides of the elongated through hole
are orientation at an angle with respect to the retaining bracket;
wherein the PCB board is mechanically attached to the housing by
inserting the retaining element on the housing through the through
hole in the PCB board such that the respective retaining flaps are
held by the retaining bracket and the respective tapering in the
through hole on the PCB board.
2. The lamp driver system recited in claim 1 wherein the housing is
capable of providing a grounded connection, and the retaining flaps
on the housing are conductive, and further wherein the retaining
bracket is conductive and is electrically connected to the PCB to
provided a grounded connection when the PCB board is connected to
the housing with the retaining bracket and the housing is connected
to ground.
3. The lamp driver system recited in claim 1 wherein said angle is
greater than 10 degrees.
4. The lamp driver system recited in claim 1 wherein said angle is
greater than 20 degrees.
5. The lamp driver system recited in claim 1 wherein each tapering
(3) is trapezoidal; and side (z) of the tapering (31) runs parallel
to a longitudinal side (32) of the through hole (3) which is not
tapered.
6. The lamp driver system recited in claim 1 wherein the components
of a lamp driver circuit and the retaining bracket are mounted on
the same planar surface of the PCB board.
7. The lamp driver system recited in claim 1 wherein the components
of a lamp driver circuit and the retaining bracket are mounted on
opposite planar surfaces of the PCB board.
8. The lamp driver system recited in claim 1 wherein the retaining
bracket is soldered to the PCB board.
9. The lamp driver system recited in claim 1 wherein the retaining
element is bowed and extends over the through hole in the PCB
board.
10. The lamp driver system recited in claim 1 wherein the PCB board
is rectangular and includes positioning holes near the corners of
the PCB board, and the housing includes corresponding positioning
elements.
11. The lamp driver system recited in claim 1 wherein the housing
and the retaining flaps are integral components made from stamped
metal.
12. The lamp driver system recited in claim 1 wherein the
components of the lamp driver circuit mounted on the PCB board
comprise at least one of the following: a rectifier, a clocked
converter, a transformer, a battery, and input and output
interfaces.
13. The lamp driver system recited in claim 1 wherein the taperings
each comprise a projection from the respective longitudinal side of
the through hole in the PCB board.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is the U.S. national stage application of
International Application PCT/EP2016/076879 filed Nov. 7, 2016,
which international application was published on May 26, 2017 as
International Publication WO 2017/084906 A1. The International
Application claims priority to German Patent Application 10 2015
222 847.6 filed Nov. 19, 2015.
FIELD OF THE INVENTION
The invention relates to a circuit board and a system composed of a
circuit board and a housing, preferably for a circuit for operating
a lamp, e.g. a driver circuit or ballast, or an electronic ballast
(abbreviated to EVG in German (Elektronisches Vorschaltgerat)). The
invention relates in particular to the optimization of a retaining
connection between the housing and the circuit board.
BACKGROUND OF THE INVENTION
Circuits for operating at least one lamp, e.g. an LED or gas
discharge lamp are preferably disposed on a circuit board. The
circuit board is provided with a housing to protect this circuit
from external effects such as dirt, mechanical disruptions,
moisture or electromagnetic radiation, and to protect people and
the environment from the circuit, e.g. by coming in contact with
conducting parts of the circuit, or from the radiation emitted by
the circuit. The housing can also accommodate other elements in
addition to the circuit board.
If the housing is made of a metallic material, for example, then it
must also be ensured for safety reasons that a ground of the
voltage supply is connected to the housing.
A mechanical retaining connection, in particular a clamping
connection between the housing and the circuit board, is normally
enabled by a housing retaining element. This retaining element is
inserted through a hole in the circuit board, and mechanically
secured by a retaining bracket. In doing so, the retaining element
of the housing is not in contact with, or sufficiently in contact
with the inner wall of the hole. The retaining connection can be
strongly impaired as a result, when the circuit board is subjected
to a mechanical load, e.g. when testing the circuit board, or when
an electrical contact is established, or when the circuit is
installed in the lighting system.
Conventionally, the housing is thus only inadequately mechanically
secured to the circuit board. If the mechanical retaining
connection is fragile, the circuit board is insufficiently
protected against external effects, and the environment is not
protected from the effects of the circuit board.
Moreover, due to the insufficient physical contact between the
through-hole and the retaining element of the housing, the
retaining force or clamping force of the retaining element may be
reduced, resulting in an additional reduction in the quality of the
mechanical securing. This impaired mechanical securing can lead in
particular to a reduction in the quality of the ground connection
between the housing and the circuit board, and in particular may
lead to disruptions or breakdowns of the lamps when the circuit is
tested or used.
The object of the present invention is therefore to create a
circuit board that can be reliably protected by a housing, wherein
the mechanical retaining connection of the housing to the circuit
board is substantially improved. In particular, an electrical
connection for applying a ground between the housing and the
circuit board should be reliably formed, in order to improve safety
when working with the housing. The mass-produced electronic circuit
for a lamp should not be more expensive, and should still to be
able to be produced easily.
This problem is solved with the technical features described
herein.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, a circuit board is
provided, preferably for a circuit for operating a lamp. The lamp
preferably comprises at least one LED. The circuit board has a
retaining bracket disposed on a planar surface of the circuit board
and mechanically connected to the circuit board. A retaining
bracket is thus provided, which is secured to the circuit board.
The mechanical connection of the retaining bracket is either
releasable, e.g. through soldering, screwing or clamping, or
permanent, e.g. through adhesive or rivets. The retaining bracket
is thus configured for retaining a housing on the circuit board, in
order to protect the circuit board.
The circuit board also has a through hole that is located at least
partially beneath the retaining bracket. The through hole thus
extends from the upper surface of the circuit board to an opposite
lower surface of the circuit board.
According to the invention, the through hole has at least one
structural tapering. This tapering substantially restricts the
freedom of movement of the retaining element of a housing within
the through hole. The tapering ensures in particular that the
retaining element comes in physical contact with the through hole.
The tapering comprises a projection or constriction within the
through hole, for example. This tapering partially reduces the
inner diameter of the through hole.
As a result, a housing can be more effectively mechanically secured
to a circuit board as a result of the retaining bracket and the
tapering. Because the retaining element has no freedom of movement,
or very little, the housing is tightly secured to the circuit
board, and is not released when a strong load is applied to the
circuit board in relation to the housing. Because the freedom of
movement is strongly reduced, it is also ensured that the retaining
connection will remain stable over a long period of time with the
intended use (testing, wiring, etc.) of the circuit, and there is
therefore no need to fear that the housing will come loose from the
circuit board. As a result, a loose connection, e.g. such that it
can wobble, due to the lack of a mechanical securing in the through
hole, is prevented. The tapering ensures that the housing, or the
retaining element of the housing, is seated tightly in the through
hole, such that a load applied later to the circuit board, e.g. for
testing the driver circuit, or the wiring of the circuit when the
lighting system is activated, does not result in the housing coming
loose from the circuit board, thus failing to protect it from
electromagnetic radiation, moisture or dirt.
This restriction of the freedom of movement of the housing as a
result of the tapering already has advantages when attaching the
housing to the circuit board, because the movement radius of the
housing is restricted. As a result, the retaining element of the
housing does not become bent apart when placed on the circuit
board, and this mechanical retaining connection is not loosened by
a relative displacement of the circuit board within the
housing.
In a preferred design, the retaining bracket is electrically
connected to a ground. The tapering thus fulfills two functions, in
that the housing can be secured mechanically to the circuit board,
and at the same time, a reliable electrical connection is
established between the housing and the circuit board.
The housings for electronic ballasts are preferably made of metal,
in order to provide a mechanical protection as well as a shielding
against electromagnetic radiation. The grounding of the housing is
intended to produce a defined reference potential or a potential
equalization, through which an incorrect voltage occurring on the
housing is short circuited. According to standardized guidelines in
building technology, metallic housings must be grounded.
By improving the mechanical retaining connection, the electric
contact between the housing and the circuit board is also improved.
A loose retaining connection results in a weak or partially
interrupted electrical connection. The safety and functionality of
such a circuit board are thus substantially increased. The
formation of the retaining bracket as a grounding conductor makes
it possible to efficiently produce a circuit for operating lamps,
because the double function is reliably produced with a single
connection. In particular, by providing a tapering in the through
hole, it is ensured that the grounding conductor is always in
contact with the housing--thus electrically connected--such that
when testing the circuit on the circuit board, or when installing
it in a lighting system, a corresponding electrical and mechanical
connection is also ensured.
In a preferred design, the through hole is an elongated hole when
viewed from above the circuit board, wherein the longitudinal sides
of the elongated hole run at an angle beneath the retaining bracket
that is greater than 0.degree., preferably greater than 10.degree.,
more preferably greater than 30.degree..
When viewed from above the circuit board, the through hole meets
the retaining bracket at an angle of greater than 0.degree.. By
increasing the angle between the longitudinal side and the
retaining bracket the retaining force is increased, because the
retaining element is then oriented more transverse than
longitudinally to the retaining bracket, and the distance between
the retaining element and the retaining bracket is reduced.
An elongated hole is a longitudinal through hole in this case. Its
narrower transverse sides preferably form semicircles, the
diameters of which correspond to the width of the elongated hole.
The longitudinal sides of the elongated hole preferably run
parallel to one another. By using an elongated hole as the through
hole, it is ensured that a larger retaining element is used, as a
result of which, larger housings can be used, or a stronger
retaining force can be obtained.
If a retaining element of the housing is then used that has, e.g.
two retaining axes and a slit running through the middle, the
retaining element can then be placed in the elongated hole such
that it is held in place along each retaining axis by the retaining
bracket and the tapering.
In a preferred design, the through hole is an elongated hole viewed
from above the circuit board, wherein at least two taperings are
disposed on opposing longitudinal sides of the through hole. In
this manner, the housing is retained more effectively in the
through hole, because two opposing taperings and the retaining
bracket then mechanically secure the housing in the circuit board's
through hole. The taperings are disposed close to the semicircles
of the elongated hole, for example.
In a preferred design, the at least one tapering has a trapezoidal
shape, wherein a tapering surface of the tapering runs parallel to
a longitudinal side of the through hole. A trapezoidal shape of the
tapering can be easily produced, and also makes it possible to
obtain a large overlapping region between the through hole and the
retaining element. As a result, a larger surface of the retaining
element of the housing is in physical contact with the through
hole, resulting in an increased mechanical securing. As a result,
the housing is disposed in an improved manner on the circuit
board.
In another preferred design, the retaining bracket is attached to
the circuit board by means of a soldered connection. As a result,
the retaining bracket can be mechanically connected to the circuit
board in a simplified production process. As a result, the
retaining bracket is attached to the circuit board in a manner
similar to that of all of the circuit elements of the circuit
populating the circuit board, such that no additional production
processes are needed for connecting the retaining bracket to the
circuit board. The retaining bracket can be an uninsulated wire,
e.g. made of copper, nickel, or iron. The retaining bracket can be
galvanized, e.g. with tin, silver, or noble metals. The retaining
bracket can be bowed.
In a preferred design, circuit elements of a circuit for operating
a lamp are disposed on a lower surface of the circuit board lying
opposite the upper surface. The housing protects the circuit
underneath the housing in this manner, wherein the housing is
inserted into the circuit board, and is secured in the through
hole.
In an alternative design, circuit elements of a circuit for
operating a lamp are disposed on the upper surface of the circuit
board. As a result, it is not necessary to populate the circuit
board on both sides in order to produce both a mechanical retaining
connection and a reliable electrical connection between the housing
and the circuit board. By clamping the retaining element in place
by means of the tapering and the retaining bracket, it is possible
to populate the circuit board on just one side. Moreover, the
retaining bracket thus does not protruded above the upper surface
of the circuit board. Because the retaining element is then
disposed on the same side as the circuit elements, and the height
of the retaining bracket is lower than the heights of the circuit
elements, this results in a miniaturization of the circuit.
In a preferred design, the retaining bracket is disposed in the
interior of the circuit board, thus between the upper surface of
the circuit board and the opposing lower surface. As a result, the
retaining bracket is integrated in the circuit board, and thus does
not rise above the upper surface or extend below the lower surface
of the circuit board. As a result, the circuit board can be
miniaturized.
In a preferred design, the through hole is tapered by the tapering
by at least 10%, preferably 15%, more preferably 20%. Different
degrees of tightening are enabled by these different taperings. A
larger tapering results in greater retaining forces in the
retaining connection between the housing and the circuit board.
According to a further aspect of the invention, a system for a
circuit for operating at least one lamp is proposed, composed of a
circuit board according to the type described above, and a housing.
The housing protects the circuit board from external effects, such
as moisture, dirt, etc. and shields the circuit disposed on the
circuit board from electromagnetic radiation.
The housing can also assume the function of a cooling element. It
would also be possible to provide a plastic coating beneath the
housing, in order to electrically insulate the housing from the
environment of the system.
According to a preferred design, the housing has at least one
retaining element, which is placed in the through hole in order to
mechanically secure the housing on the circuit board by means of
the retaining bracket and the tapering. By way of example, with a
rectangular circuit board there are four additional holes in the
corners or the edges of the circuit board, in which four
positioning elements of the housing can be placed according to the
invention, in order to produce the mechanical, and potentially
electrical, connection between the housing and the circuit board.
An additional one or two through holes are also provided in the
circuit board in which one or two retaining elements of the housing
can be placed according to the invention, in order to produce the
mechanical, and potentially electrical, connection between the
housing and the circuit board.
The retaining element preferably extends upward from the housing.
This extension is understood in the following to be a retaining
element that can be produced by means of a production process. By
way of example, portions of the housing are stamped out thereby,
and the inner region of the stamping is bent over appropriately.
This results in a retaining element that is made of the same
material as the housing and obtained through a simple material
processing.
The retaining element preferably has at least two retaining flaps,
wherein the retaining flaps are preferably identical. There is a
slot located centrally between the flaps, produced for example in a
stamping or cutting process. When such a retaining element of the
housing is then secured in the through hole, the retaining flaps
are separated by the retaining bracket. This results in a securing,
wherein each retaining flap is tightened around the retaining
bracket by means of a tapering in the through hole.
The retaining element is preferably mechanically secured with the
retaining flap to the retaining bracket and a first tapering. In
addition, the second retaining flap is mechanically secured by
means of the retaining bracket and a second tapering. As a result,
the retaining element is tightened in place, wherein the retaining
bracket runs through a slot between retaining flaps. The tapering
is then provided such that in each case, one side of the retaining
flap is in direct physical contact with the interior of the through
hole. As a result, the retaining element has no freedom of movement
in the through hole after placing the housing on the circuit board,
and is tightened in place. As a result, the retaining flaps of the
retaining element cannot be bent apart beyond a certain extent when
attaching the housing to the circuit board, such that the
mechanical retention, as well as the electrical connection, are not
released when a physical force is applied to the circuit board in
relation to the housing.
In a preferred design, at least one flap of the retaining element
is mechanically secured in the through hole by the tapering and the
retaining bracket.
In a preferred design, the at least one retaining flap of the
retaining element has a longitudinal side, wherein this
longitudinal side of the retaining flap bears on at least 25% of
the tapering. As a result, the retaining flap is in physical
contact with the printed circuit board over most of the through
hole, and in particular, is mechanically secured thereto by the
retaining bracket and the tapering. A very stable retaining
connection and a reliable grounding connection are obtained in this
manner.
In a further aspect of the invention, a method for securing a
housing to a circuit board is provided. The method comprises the
following steps: placing the retaining bracket on an upper surface
of the circuit board above a through hole, wherein the through hole
has at least one tapering; placing a retaining element of the
housing in the interior of the through hole, wherein the retaining
element has at least two retaining flaps and one slot; and wherein
the retaining bracket is inserted through the slot, such that the
retaining element is mechanically secured by the retaining bracket
and the tapering.
The invention, and further embodiments and advantages of the
invention shall be described in greater detail below based on the
figures, wherein the figures only describe exemplary embodiments of
the invention. Identical components in the figures are provided
with identical reference symbols. The figures are not to be
regarded as drawn to scale, and some elements of the figures may be
enlarged or simplified.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first exemplary embodiment of a system according to
the invention;
FIG. 2a shows a first exemplary embodiment of a circuit board
according to the invention;
FIG. 2b shows a second exemplary embodiment of a system according
to the invention;
FIG. 3a shows a third exemplary embodiment of a system according to
the invention;
FIG. 3b shows a fourth exemplary embodiment of a system according
to the invention;
FIG. 4 shows a fifth exemplary embodiment of a system according to
the invention;
FIG. 5 shows a second exemplary embodiment of a circuit board
according to the invention.
DETAILED DESCRIPTION
FIG. 1 shows a first exemplary embodiment of a system according to
the invention. A circuit board 1 is shown therein as a planar plate
in a cross section. The circuit board 1 has a retaining bracket 2.
The retaining bracket 2 is mechanically connected to the circuit
board 1 at two soldering points 21 in the form of a bowed arch
above the circuit board 1. The retaining bracket 2 is thus
connected to the circuit board 1 such that it can be mechanically
released therefrom and secured thereto. Instead of soldering points
21, welding points, screw connections, adhesive, or other
mechanical securing means can be selected. The retaining bracket 2
can be an uninsulated wire, e.g. made of copper, nickel or iron.
The retaining bracket 2 can be galvanized, e.g. with tin, silver or
a noble metal.
The circuit board 1 also has a through hole 3, which is located at
least partially underneath the retaining bracket 2. The through
hole 3 extends from a first upper surface 11 of the circuit board 1
to a lower surface 12 of the circuit board 1. The through hole 3 is
in the form of an elongated hole, in particular.
According to FIG. 1, a housing 5 is provided, which has at least
one retaining element 4. This retaining element 4 extends upward.
This extension is a part of the housing 5 obtained in a stamping
and bending process. The retaining element 4 according to FIG. 1
has two identical retaining flaps 41, separated in the center by a
slot 42. The slot 42 can be obtained through stamping or
cutting.
In order to then mechanically secure the housing 5 to the circuit
board 1, the retaining element 4 is inserted through the circuit
board 1 from the lower surface 12. The retaining flaps 41 are then
spread apart on the retaining bracket 2 located on the upper
surface 11 of the circuit board 1, such that the slot 42 is
temporarily widened when the housing is placed on the circuit board
1. The retaining bracket 2 is then in the region of the slot 42 in
the retaining element 4 after the housing 5 has been placed
thereon.
It is not shown in FIG. 1 that the through hole 3 has a tapering
31. The retaining element 4 is mechanically secured in the through
hole 3 by means of this tapering 31 and the retaining bracket 2
such that the retaining flaps 41 bear on the tapering 31 and are
thus in physical contact with the interior wall of the through hole
3. As a result, the retaining element 4 is held in place between
the tapering 31 and the retaining bracket 2. The freedom of
movement of the retaining element 4 in the through hole 3 is thus
substantially reduced, or eliminated, such that the retaining
connection cannot be easily released, in particular when a
mechanical load is applied to the circuit board 1 in relation to
the housing as a result of testing or when a circuit is put in
operation on the circuit board 1 when installed in a lighting
system, and also cannot be inadvertently impaired, in particular
such that it becomes unstable, or loosened.
It is also provided that the retaining bracket 2 is electrically
connected to a ground. As a result, the retaining bracket 2 also
provides a grounding connection. A grounding connection is useful,
for example, when an electrical connection must also be created by
means of the connection between the housing 5 and the circuit board
1, if the housing 5 is made of a metallic material, for example. As
a result, the housing 5 is grounded, and it is mechanically secured
to the circuit board 1.
FIG. 2a shows a top view of an upper surface 11 of a first
exemplary embodiment of a circuit board 1 according to the
invention. This is shown in a view from above. It can be seen
therein that the through hole 3 has the shape of an elongated
hole--depicted stylistically herein as a rectangle. The transverse
sides, which are orthogonal to the longitudinal sides 32, can take
the form of semicircles, for example. The elongated hole 3 has two
taperings 31 on opposing longitudinal sides 32. The longitudinal
sides 32 of the through hole 3 are disposed at an angle .alpha.
greater than 0.degree. in relation to a longitudinal orientation of
the retaining bracket 2. By altering the angle .alpha., the
retaining force of the mechanical securing can be adjusted.
The tapering 31 tapers the through hole 3. Thus, the transverse
dimension x of the through hole 3 at the height of the retaining
bracket 2 is greater than a transverse dimension y in the region of
the tapering 31. The tapering 31 is in the form of a trapezoidal
projection. The trapezoidal shape of the projection 31 enables a
retaining element 4 to come in contact with the inner walls of the
through hole 3 in a comparably large region of the longitudinal
side 32 of the elongated hole 3. As a result, the mechanical
securing of the housing 5 to the circuit board 1 is substantially
improved.
A second exemplary embodiment of a system according to the
invention is shown in FIG. 2b. The circuit board 1 illustrated in
FIG. 2a is shown therein with a housing 5, and a retaining element
4 of the housing 5. The retaining element 4 is designed in
accordance with FIG. 1, by way of example, and has two retaining
flaps 41, 41', which are placed in the interior of the through hole
3. A retaining bracket 2 separates the retaining flaps 41, 41' in
the region of the slot 42. Because the tapering surface z of the
tapering 31 runs over a significant portion of the longitudinal
side of a flap 41, the retaining element 4 is mechanically secured
at both sides of the elongated hole 3, and in physical contact with
the through hole. The retaining flaps 41, 41' are tightened by
means of the tapering 31 and the retaining bracket 2. As a result,
the retaining flaps 41 of the retaining element 4 cannot bend
apart, because the freedom of movement of the retaining flaps 41 in
the through hole 3 is substantially restricted, such that the
housing 5 is not released even when the circuit board 1 is
displaced in relation to the housing 5.
The retaining elements 4 of the housing 5 in the form of grounding
projections are thus clamped more strongly than without projections
31, and permanently secure the housing 5 to the circuit board 1. As
a result, a permanent reliable grounding connection is also
obtained.
A third exemplary embodiment of a system according to the invention
is shown in FIG. 3a. There are at least two retaining brackets 2
disposed on the upper surface 11 of the circuit board 1 at the
corners of the circuit board 1. The housing 5 has at least two
retaining elements 4, which are mechanically secured to the
retaining bracket 2 in accordance with FIG. 1 or FIG. 2b,
respectively. FIG. 3 also shows that circuit elements 6, 6' are
disposed on the lower surface 12 of the circuit board 1, which can
form a circuit for operating a lamp. These circuit elements 6, 6'
comprise a rectifier, a clocked converter, a transformer, a battery
serving as a secondary voltage supply, and input and output
interfaces, by way of example. In order to protect these circuit
elements 6, 6' from external effects, it is provided that the
housing 5 is mechanically secured to the circuit board 1. The
housing 5 is made of aluminum, for example, and must be grounded.
For this, the connection between the retaining element 4 and the
retaining bracket 2 is also an electrical contact with a
ground.
A fourth exemplary embodiment of a system according to the
invention is shown in FIG. 3b. In differing from FIG. 3a, it is
provided that the retaining bracket 2 is formed on the same side as
the circuit elements 6, 6'. According to FIG. 3b, this is the upper
surface 11 of the circuit board 1. The mechanical securing by means
of the retaining bracket 2 and the tapering 31 is not worse than
that according to FIG. 3a, but it is no longer necessary to
populate the circuit board 1 on both sides. This simplifies
production, and reduces the structural height of the system,
because the height of the retaining bracket 2 is lower than the
height of the circuit elements 6, 6'.
A fifth exemplary embodiment of a system according to the invention
is shown in FIG. 4. In differing from FIG. 1, the retaining bracket
2 is disposed within the interior of the circuit board 1, thus
between the upper surface 11 and the lower surface 12. This reduces
the structural height of the system and improves the mechanical
stability of the connection of the retaining bracket 2 to the
circuit board 1.
A second exemplary embodiment of a circuit board 1 is shown in FIG.
5 in a top view. In differing from FIG. 2a, the projections 31 have
alternating shapes. In accordance with the left-hand projection
31', a semicircular bulge is created in the interior of the through
hole 3. In comparison, the right-hand projection 31 has a
triangular shape. The embodiment of a circuit board 1 shown in FIG.
5 shows that the tapering must only be formed such that it
restricts or fully eliminates the movement radius of the retaining
element 4, or the corresponding retaining flaps 41, 41' in the
through hole.
All of the elements described and/or illustrated and/or claimed in
the scope of the invention can be combined arbitrarily with one
another.
LIST OF REFERENCE SYMBOLS
1 circuit board 11 upper surface 12 lower surface 2 retaining
bracket, grounding conductor 21 soldering point 3 through hole,
elongated hole 31 tapering, projection 32 longitudinal side 4
retaining element 41, 41' retaining flap 42 slot 5 housing 6, 6'
circuit elements x transverse dimensions below the retaining
bracket y transverse dimensions in the region of the tapering z
tapering surface of the tapering .alpha. angle between retaining
bracket and through hole
* * * * *